The Sentier des Douaniers and Château de Costaérès

The Sentier des Douaniers is the local name for the stretch of the GR34 coast path between the Plage de Trestraou at Perros-Guirec and Ploumanac'h — about four and a half kilometres, an hour at a walking pace, and the best hour on this coast. It was cut for customs officers watching for smugglers; today it is a well-made path that climbs onto the cliff, drops to small beaches and threads between granite blocks the whole way.

The set piece is the Château de Costaérès, a granite house built in the 1890s on a small tidal island opposite the path, complete with turret and crenellations. It is private, it cannot be visited, and it is only ever photographed from the shore — which is fine, because from the path it sits in the middle distance with pink rock in the foreground and open sea behind, and it makes a portrait background nothing else on the coast can match.

Half-way along, the Maison du Littoral sits among the boulders and gives a shorter approach from the Ploumanac'h side if a full walk is not wanted. The path is exposed to the north-west, so it is windy more often than not, and the surface is uneven granite in places — not a stiletto route.

Light is best in the late afternoon, when the sun is off to the west and the rock warms up; at that hour the path is also at its busiest in summer, so start early or take the Trestraou end and walk against the flow.